Haskell Database Demo

Description:

The following sections provide an overview of key operations when working with databases in Haskell, focusing on creating a database, inserting records, and retrieving data.

1. Creating a Database and Table

In Haskell, interacting with a database typically involves using libraries such as persistent or sqlite-simple. To create a database, you first establish a connection to the database server. After successfully connecting, you can execute SQL commands to create a new database and define your data schema by creating tables. For example, you might define a users table with fields like id, name, and age, where id serves as a unique identifier, often defined as an auto-incrementing primary key.

2. Inserting Data into the Table

After the table structure is established, you can insert records into the database. This process usually involves constructing an SQL INSERT statement, specifying the values for the relevant columns in the table. In Haskell, you can use type-safe libraries to ensure that the data types match the schema, enhancing safety and reducing runtime errors. For instance, adding new users would require you to provide values for their name and age, which are then stored in the database.

3. Retrieving Data from the Table

Retrieving data from a database in Haskell is accomplished through SQL SELECT statements. Once a query is executed, you can process the results using monadic structures or data types provided by database libraries. This typically involves iterating through the returned rows and mapping the results to user-defined data types. The extracted data can then be displayed or manipulated further within your application.

Conclusion

These operations—creating a database and table, inserting records, and retrieving data—are fundamental to database interactions in Haskell. Understanding these concepts is essential for building applications that require persistent data storage, making them crucial skills for Haskell developers and relevant topics for technical interviews. Mastery of these operations also highlights your ability to work with functional programming paradigms in the context of database management.

Features:

• Create Database
• Insert into Database
• Retrieve from Database

Requirements:

Latest distribution of Haskell toolchain

Instructions:

1. Use GHCup to install and manage the Haskell toolchain.
2. Use VSCode as the editor, with the Haskell extension installed.